vfio/platform: store mapped memory in region, instead of an on-stack copy

vfio_platform_{read,write}_mmio() call ioremap_nocache() to map
a region of io memory, which they store in struct vfio_platform_region to
be eventually re-used, or unmapped by vfio_platform_regions_cleanup().

These functions receive a copy of their struct vfio_platform_region
argument on the stack - so these mapped areas are always allocated, and
always leaked.

Pass this argument as a pointer instead.

Fixes: 6e3f26456009 "vfio/platform: read and write support for the device fd"
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Baptiste Reynal <b.reynal@virtualopensystems.com>
Tested-by: Baptiste Reynal <b.reynal@virtualopensystems.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index e43efb5..8c216de 100644 (file)
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -307,17 +307,17 @@ static long vfio_platform_ioctl(void *device_data,
        return -ENOTTY;
 }
 
-static ssize_t vfio_platform_read_mmio(struct vfio_platform_region reg,
+static ssize_t vfio_platform_read_mmio(struct vfio_platform_region *reg,
                                       char __user *buf, size_t count,
                                       loff_t off)
 {
        unsigned int done = 0;
 
-       if (!reg.ioaddr) {
-               reg.ioaddr =
-                       ioremap_nocache(reg.addr, reg.size);
+       if (!reg->ioaddr) {
+               reg->ioaddr =
+                       ioremap_nocache(reg->addr, reg->size);
 
-               if (!reg.ioaddr)
+               if (!reg->ioaddr)
                        return -ENOMEM;
        }
 
@@ -327,7 +327,7 @@ static ssize_t vfio_platform_read_mmio(struct vfio_platform_region reg,
                if (count >= 4 && !(off % 4)) {
                        u32 val;
 
-                       val = ioread32(reg.ioaddr + off);
+                       val = ioread32(reg->ioaddr + off);
                        if (copy_to_user(buf, &val, 4))
                                goto err;
 
@@ -335,7 +335,7 @@ static ssize_t vfio_platform_read_mmio(struct vfio_platform_region reg,
                } else if (count >= 2 && !(off % 2)) {
                        u16 val;
 
-                       val = ioread16(reg.ioaddr + off);
+                       val = ioread16(reg->ioaddr + off);
                        if (copy_to_user(buf, &val, 2))
                                goto err;
 
@@ -343,7 +343,7 @@ static ssize_t vfio_platform_read_mmio(struct vfio_platform_region reg,
                } else {
                        u8 val;
 
-                       val = ioread8(reg.ioaddr + off);
+                       val = ioread8(reg->ioaddr + off);
                        if (copy_to_user(buf, &val, 1))
                                goto err;
 
@@ -376,7 +376,7 @@ static ssize_t vfio_platform_read(void *device_data, char __user *buf,
                return -EINVAL;
 
        if (vdev->regions[index].type & VFIO_PLATFORM_REGION_TYPE_MMIO)
-               return vfio_platform_read_mmio(vdev->regions[index],
+               return vfio_platform_read_mmio(&vdev->regions[index],
                                                        buf, count, off);
        else if (vdev->regions[index].type & VFIO_PLATFORM_REGION_TYPE_PIO)
                return -EINVAL; /* not implemented */
@@ -384,17 +384,17 @@ static ssize_t vfio_platform_read(void *device_data, char __user *buf,
        return -EINVAL;
 }
 
-static ssize_t vfio_platform_write_mmio(struct vfio_platform_region reg,
+static ssize_t vfio_platform_write_mmio(struct vfio_platform_region *reg,
                                        const char __user *buf, size_t count,
                                        loff_t off)
 {
        unsigned int done = 0;
 
-       if (!reg.ioaddr) {
-               reg.ioaddr =
-                       ioremap_nocache(reg.addr, reg.size);
+       if (!reg->ioaddr) {
+               reg->ioaddr =
+                       ioremap_nocache(reg->addr, reg->size);
 
-               if (!reg.ioaddr)
+               if (!reg->ioaddr)
                        return -ENOMEM;
        }
 
@@ -406,7 +406,7 @@ static ssize_t vfio_platform_write_mmio(struct vfio_platform_region reg,
 
                        if (copy_from_user(&val, buf, 4))
                                goto err;
-                       iowrite32(val, reg.ioaddr + off);
+                       iowrite32(val, reg->ioaddr + off);
 
                        filled = 4;
                } else if (count >= 2 && !(off % 2)) {
@@ -414,7 +414,7 @@ static ssize_t vfio_platform_write_mmio(struct vfio_platform_region reg,
 
                        if (copy_from_user(&val, buf, 2))
                                goto err;
-                       iowrite16(val, reg.ioaddr + off);
+                       iowrite16(val, reg->ioaddr + off);
 
                        filled = 2;
                } else {
@@ -422,7 +422,7 @@ static ssize_t vfio_platform_write_mmio(struct vfio_platform_region reg,
 
                        if (copy_from_user(&val, buf, 1))
                                goto err;
-                       iowrite8(val, reg.ioaddr + off);
+                       iowrite8(val, reg->ioaddr + off);
 
                        filled = 1;
                }
@@ -452,7 +452,7 @@ static ssize_t vfio_platform_write(void *device_data, const char __user *buf,
                return -EINVAL;
 
        if (vdev->regions[index].type & VFIO_PLATFORM_REGION_TYPE_MMIO)
-               return vfio_platform_write_mmio(vdev->regions[index],
+               return vfio_platform_write_mmio(&vdev->regions[index],
                                                        buf, count, off);
        else if (vdev->regions[index].type & VFIO_PLATFORM_REGION_TYPE_PIO)
                return -EINVAL; /* not implemented */